The prior art discloses the shaping of flat, circular aluminium pieces by drawing so as to form cylindrical containers, which are internally and externally varnished and then the container opening is narrowed by drawing in and flanging and made ready for the attachment of a cap or closure. Such containers are e.g. further processed to form aerosol monoblock containers. Varnishing and in particular the printing of inscriptions or decorative patterns prior to drawing in is advantageous, because lacquer or varnish can only be rolled on to cylindrical containers. Even internally, where the varnish is sprayed on, this can take place more easily on the still cylindrical container.
Varnishing the insides of aluminium containers is necessary for all those applications in which a bare aluminium surface would be attacked by the container contents. Whenever during storage and use the container content comes into contact with the container inner surface, it is important for the internal varnish to cover said surface in an absolutely uninterrupted manner.
For the methods for the manufacture of varnished aluminium containers according to the prior art, varnishes have been developed, which are so adhesive, elastic and slidable that cylindrical, varnished aluminium containers can be drawn in in bottle-like manner without damaging the varnish.
As aluminium is a very satisfactory and inexpensively recyclable packing material, it would be appropriate and desirable if it would be possible to manufacture, from aluminium, containers onto which could e.g. be screwed a hand pump with a riser tube or a screw cap, in the same way as with plastic or glass bottles. The aluminum container could e.g. be marketed filled with the screw cap closed. The consumer would only have to screw and then unscrew the multiply usable pump onto the aluminum container and to either refill or recycle the container without extraneous material. For this purpose aluminum containers with corresponding threads and advantageously standardized threads are necessary.